JPS6338069A - Slip controller for automobile - Google Patents

Abstract

PURPOSE:To permit the optimum control for both of the slip control and the ordinary traveling control by installing a control means which attaches importance to stability and a control means which attaches importance to responsiveness as the control means for the output torque and selectively using these means according to the slip state. CONSTITUTION:When the excessive increase of the slip for a road surface of a driving wheel is prevented by controlling the output torque for the driving wheel of a power plant system at least including an engine by a torque control means A, the first control means B which takes a serious view of stability and the second control means C which takes a serious view of response speed are provided as the control means for the output torque of the power plant system. These control means B and C are selectively used by a selecting means D according to the result of the judgement for the present state in slip or not. In other words, if the state at present is in slip, the first control means B is selected to control the torque adjusting means A, while in the ordinary traveling control, the second control means C is selected.

Description

[Detailed Description of the Invention] (Field of Industrial Application) The present invention prevents excessive slip of the driving wheels against the road surface by controlling the output torque to the driving wheels of a power plant system. This invention relates to a slip control device for an automobile.

(Prior art) Preventing the slip and slump of the driving wheels relative to the road surface from becoming excessive is effective in obtaining the propulsive force of the vehicle, and is also effective in terms of safety by preventing spin. In order to prevent the slip of the drive wheels from becoming excessive, it is necessary to appropriately control the torque applied to the drive wheels.

Conventionally, methods for performing this type of slip control are disclosed in Japanese Patent Application Laid-Open No. 58-16948 or Japanese Patent Application Laid-Open No. 60-56.
There is one shown in Publication No. 662.

Both of the technologies disclosed in these publications use the braking force applied to the drive wheels by the brake and the reduction in torque generated by the engine to control the torque applied to the drive wheels. ing. More specifically, JP-A-58-1
According to the No. 6948 publication, when the slip of the drive wheels is small, only the braking of the drive wheels is performed, but when the slip of the drive wheels becomes large, in addition to the braking of the drive wheels, the engine is braked. It is designed to reduce the generated torque. In addition, in the method disclosed in Japanese Patent Application Laid-open No. 60-56662, when the slip of only one of the left and right drive wheels is large, braking is applied only to the drive wheel of the one side with the large slip, while When the slip of both drive wheels is large, braking is applied to both drive wheels and the torque generated by the engine is reduced.

(Problems to be Solved by the Invention) Recently, with the advancement of electronic control of automobiles, there are an increasing number of automobiles that are electronically controlled, such as throttle valves, transmissions, etc.

When adding the above-mentioned slip control to this type of automobile, two forms of control are provided: normal running control and slip control. Therefore, these two
In order to optimize each type of control, it is desirable to consider the requirements for each type of control in each control form.

For example, to specifically explain a vehicle in which the throttle valve is electronically controlled, in normal driving control, it is preferable that the response speed is high in order to improve the driving feeling. On the other hand, in slip control, it is preferable to have one L that improves slip convergence and is strong against disturbances.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a slip control device for an automobile that is equipped with two forms of electrical control, normal running control and slip control, and is capable of optimizing each control. shall be.

(Means and effects for solving the problem) In order to achieve the above object, the present invention provides a control system that emphasizes stability and a control system that emphasizes response speed using normal running control and slip control. It is possible to switch between the two.

In other words, as shown in FIG. 20, the slip control for an automobile prevents excessive slip of the drive wheels relative to the road surface by controlling the output torque to the drive wheels of the power plant system including at least the engine. Assuming that the device is a torque adjusting means for adjusting the output torque of the power plant system, a first control means emphasizing stability as a control means for setting the output torque of the power plant system as a target value, and a first control means that emphasizes response speed. It has a second control means that focuses on

With such a configuration, it is possible to obtain a control method depending on the control form.

(Example) Examples of the present invention will be described below based on the attached drawings.

Overview of overall configuration In Fig. 1, a car l has left and right front wheels 2 which are drive wheels.
．． 3 and left and right rear wheels 4.5 serving as driven wheels. At the front of Medo 11, an engine 6, a clutch 7, a transmission 8, and a differential gear 9 are mounted as a power plant system, and the output torque is transmitted to drive wheels via left and right drive shafts 10 and 11. It is transmitted to the left and right wheels 111j 2.3. In this way, the car 1 is a FF type (front engine/front drive)
It is said to belong to

The engine 6 is configured to have load control, that is, control of generated torque, by a throttle valve 13 disposed in an intake passage 12 thereof. More specifically, the engine 6 is a gasoline engine, and the generated torque changes depending on the change in the intake air amount, and the intake air amount is adjusted by the throttle valve 13. The throttle valve 13 is electromagnetically controlled to open and close by a throttle actuator 14. It should be noted that the throttle actuator 14 may be constructed of any suitable type, such as a DC motor, a stem motor, or one driven by fluid pressure such as oil pressure and electromagnetically controlled.

1 each ((The wheels 2 to 5 have brakes 21, 22, respectively.
23 or 24 are provided, and each of the brakes 21 to 24 is a disc brake. As is known, this disc brake includes a disc 25 that rotates together with the wheel and a caliper 26. This caliper 26 holds a brake pad and is equipped with a wheel cylinder, and a braking force is generated by pressing the brake pad against the disc 25 with a force corresponding to the magnitude of brake fluid pressure supplied to the wheel cylinder. .

The mask cylinder 27 as a brake fluid pressure generation source is 2
It is of a tandem type having two discharge ports 27a and 27b. The brake pipe 28 extending from the discharge port 27a is branched into two branch pipes 28a and 28b in the middle, and the branch pipe 28a is connected to the right front wheel brake 22 (wheel cylinder).
The branch pipe 28b is connected to the left rear wheel brake 23. Further, the brake pipe 29 extending from the discharge port 27b is branched into two branch pipes 29a and 29b in the middle, the branch pipe 29a is connected to the left front wheel brake 214.1, and the branch pipe 29b is the right rear wheel brake. 24. In this way, the brake piping system is
It is considered to be type X. An electromagnetic hydraulic pressure control valve 30 or 31 as a braking force adjustment stage F is connected to the branch pipes 28a and 29a for the brakes 21 and 22 for the front wheels, which are the driving wheels. Of course, mask cylinder 2
The brake fluid pressure generated at step 7 corresponds to the amount of depression (depression force) of the brake pedal 32 by the driver.

Brake Hydraulic Pressure Control Circuit As shown in FIG. 2, each of the hydraulic pressure control valves 30, 31 has a cylinder 41 and a piston 42 that is slidably inserted into the cylinder 41. The piston 42 defines the inside of the cylinder 41 into a variable volume chamber 43 and a control chamber 44 . This variable volume chamber 43 is
It serves as a passageway for brake fluid pressure from the mask cylinder 27 to the brake 21 (22). Therefore, by adjusting the displacement position of the piston 42, the volume of the variable volume chamber 43 is changed, and the brake 21 (22)
This means that the brake fluid pressure can be increased, decreased or maintained.

The piston 42 is constantly urged by a return spring 45 in a direction in which the volume of the variable volume chamber 43 increases. Further, a check valve 46 is integrated into the piston 42. This check valve 46 is connected to the piston 4.
2 is displaced in the direction of decreasing the volume of the variable volume chamber 43, the inlet side to the variable volume chamber 43 is closed.

As a result, the brake fluid pressure generated in the variable volume chamber 43 acts only on the brake 21 (22) side, and does not act on the brake 23, 24 of the rear wheel 4.5 as a driven wheel. There is.

The displacement position of the piston 42 is adjusted by adjusting the control hydraulic pressure to the control chamber 44. To explain this point in detail, the supply pipe 48 extending from the reservoir 47 is branched into two in the middle, and one branch pipe 48R is connected to the valve 30.
The other branch pipe 48L is connected to the control chamber 44 of the valve 31. A pump 49 and a relief valve 50 are connected to the supply pipe 48, and a supply valve SV3 (SV2) consisting of an electromagnetic on-off valve is connected to the branch pipe 48L (48R). Each control chamber 44 is further connected to the reservoir 47 via a discharge pipe 51R or 51L, and a discharge valve SV4 (SVI) consisting of an electromagnetic on-off valve is connected to the discharge pipe 51L (51R).

During braking (slip control) using this hydraulic pressure control valve 30 (31), the check valve 46 acts, so basically the brakes that are operated by the brake pedal 32 do not move. When the brake fluid pressure generated by the fluid pressure control valve 30 (31) is small (for example, during depressurization), the brake will be applied by operating the brake pedal 32.Of course, the brake fluid pressure generated by the fluid pressure control valve 30 (31) will be applied.
(31), when brake fluid pressure for slip control is not generated, the mask cylinder 27 and brake 21 (22)
) are in communication, so normal braking action will be performed due to the operation of the brake hydraulic pressure lever 27.

The opening and closing of each of the valves 5VI-3V4 is controlled by a brake control unit (UB), which will be described later. Brake fluid pressure status to brakes 21 and 22 and each valve SV
The operational relationship with SV1 to SV4 is summarized and shown on the robe.

(Hereinafter, blank space) Overview of control unit configuration Q'r l In the figure, U is a control unit, which can be roughly divided into the brake control unit UB mentioned above, the throttle control unit UT, and the slip control control unit. Us
It is composed of. Based on the command signal from the control unit US, the control unit 2 and U8
As described above, the opening and closing of each valve 5VI-3V4 is controlled. In addition, the throttle control unit UT is
Drive control of the throttle actuator 14 is performed based on command signals from the control unit US.

The slip control control unit (US) is constituted by a digital computer, more specifically a microcomputer. Signals from each sensor (or switch) 61 to 68 are input to this control unit Us. The sensor 61 detects the opening degree of the throttle valve 13. The sensor 62 detects whether the clutch 7 is engaged.

The sensor 63 detects the gear stage of the gear shift a8.

Sensors 64 and 65 detect the rotational speed of the left and right wheels 2.3 as driving wheels. The sensor 66 detects the rotation speed of the left rear wheel 4 as a driven wheel, that is, -1 (speed). The sensor 67 detects the operation amount of the accelerator 69, that is, the accelerator opening. The sensor 68 detects the rotation speed of the left rear wheel 4 as a driven wheel. 70, the operation 7, t, that is, the steering angle is detected.The sensors 64, 65, 66 are each configured using a pickup, for example, and the sensors 61, 63, 67, .
The sensor 68 is configured by using, for example, a potentiometer, and the sensor 62 is configured by, for example, a switch that operates in an ON/OFF manner.

The control unit US is basically CPtJ.
, ROM, RAM, CLOCK, etc.
In addition to being equipped with an input/output interface, it also has an A/D or D/A converter depending on the input signal and output signal, but in these respects it is different from the normal one when using a microcomputer. Since there is no,
A detailed explanation thereof will be omitted. Note that the maps and the like in the following explanation are stored in the ROM of the control unit Us.

Next, the control contents of the control unit U will be explained in order, and the slip rate S used in the following explanation shall be defined by the following equation (1).

WD: Number of revolutions of the driving wheels (2, 3) WL: Number of revolutions of the driven wheels (4) (vehicle speed) The throttle control control unit UT provides feedback to the throttle valve 13 (throttle actuator 14) so that the target throttle opening is achieved. It is supposed to be controlled. During this throttle control, when slip control is not performed, the control is performed so that the throttle opening is [-1] corresponding to l:l based on the operation amount of the accelerator 69 operated by the driver. An example of the correspondence between the accelerator opening and the throttle opening is shown in FIG. 14. Also,
During slip control, the control unit UT
Without following the characteristics shown in FIG. 14, the throttle control is performed so as to achieve the target throttle opening degree Tn calculated by the control unit (US).

This throttle control is performed using the I-FD control method (first control means) (FIG. 3), which is resistant to disturbance and has excellent stability.
and PID control method (second control means) with excellent response speed.
It is possible to selectively adopt two control methods (Fig. 4).

That is, in the I-FD control method, the manipulated variable Mn is calculated by the following equation (2).

Mn=Mn-1+KI (xn-”In)+KP
(xn -yn -xn-1+yn-1)-F
P(yn-yn-x)-FD(yn-
2yn-1+yn-2) fist ・ ・ (2) KI: Integral constant KP: Proportional constant FP: Proportional constant FD: Differential constant On the other hand, in the PID control method, the
<Mn is calculated.

M n = M n-1 +KP ((xn -yr+) -(xn-1-yn
-1 month + KI (Xn-yn) 10KD Hxn -yn) -2(xn-1-yn-
r ) + (XJI-2-yn-February・ΦΦ (3) KD: Differential constant Also, when controlling the slip of the driving wheels, the current slip -
(The opening degree of the throttle valve 13 is feedback-controlled so that 4 coincides with the verity rate of 1,
In this embodiment, this feedback control is performed by PI-FD sub-control, as shown in FIG. More specifically, the "1 standard throttle opening degree Tn during slip control is calculated by the following equation (4).

Tn= Tn-1 -5ET -F P (WDn -WDn-1) -F D (
WDn= 2 x WDn-1+ WDn-2)...
(4) WL: Rotation speed of driven wheels (4) WD: Rotation speed of driving wheels (2, 3) KP: Proportional constant KI: vL constant FP: Proportional constant FD: Differential constant SET: Target slip rate ( For throttle control) As shown in equation (4) above, the throttle opening degree Tn is feedback-controlled on the rotational speed of the driving wheels so that it becomes a predetermined target slip rate SET. In other words, as is clear from equation (1) above, the throttle opening is determined by the target drive wheel rotation speed WE.
T is controlled so that it satisfies the following equation (5).

PI-FD using the control unit UT described above
The control is shown as a block diagram in FIG.
"S'" shown in FIGS. 3 to 5 is an operator. Further, each suffix rnJ and r n -IJ indicates the value of each signal at the current time and the previous sampling time.

During brake control slip control, the control unit) UB
The rotation (slip) of the left and right drive wheels 2.3 is feedback-controlled to a predetermined target slip rate SET independently for the left and right wheels. In other words, brake control is expressed by the following equation (
Feedback control is performed so that the driving wheel rotation speed WBT set in step 6) is achieved.

In this embodiment, the target slip rate SBT of the brake is set to be larger than the target slip rate SET of the engine, as will be described later. In other words, the slip control of this embodiment increases or decreases the engine output to a predetermined S ET (WET), and also increases or decreases the engine output to a predetermined S BT (WB
The frequency of use of the brake is reduced by increasing and decreasing the torque by the brake so that the torque becomes T). In this embodiment, feedback control that satisfies the above equation (6) is performed by I-FD control, which has excellent stability. More specifically, the brake operation amount (operation amount of the piston 44 in the valve 30, 31) B n is calculated by the following equation (7).

Bn=Bn-1 + K I (WLnX -WDn)-
3BT -F P (WDr+ -WDn-1) -F D
(WDn-2X WDn-1+ WDn-2)...
(7) KI: Integral coefficient KD: Proportional coefficient FD: Differential coefficient 1 When Bn is greater than O (“positive”), the brake fluid pressure is increased, and when it is 0 or less, it is reduced. This increase/decrease in brake fluid pressure is controlled by the valve 5VI as described above.
-3V4 is opened and closed. In addition, the adjustment of the rate of increase/decrease in brake fluid pressure is performed using the valve 5VINS mentioned above.
This is done by adjusting (duty control) the ratio of opening/closing time (duty ratio) of V4, and the duty control is proportional to the absolute value of Bn determined by the above equation (7). Therefore, the absolute value of Bn is proportional to the rate of change in brake fluid pressure, and conversely, the duty ratio that determines the rate of increase/decrease also indicates Bn.

The I-FD control by the control unit UB described above is shown in FIG. 6 as a block diagram, and "S'" shown in FIG. 6 is "operator".

Overall slip control The overall outline of the slip control by the 4FA control unit (U) will be explained with reference to FIG. The meanings of the symbols and numerical values shown in FIG. 7 are as follows.

S/C Nislip control area E/G: Slip control by engine B/R Slip control by Nibrake F/B: Feedback control 0/R: Oven loop control R/Y: Recovery control B/A: Backup control A/S: Buffer control S = 0.2 Slip rate at the start of Nislip control (SS) S = 0.17: Target slip rate by brake (S ET
) S = 0.09 Slip rate when stopping slip control by brake (S BC:) S = 0.06: Target slip rate by engine CS ET
) S = 0.01 to 0.02: Slip rate in the range where buffer control is performed S = 0.01 or less: Slip rate in the range where backup control is performed The figures are shown in l and % based on the data obtained by running the car. Then, S = 0.01 and 0.02 for performing the buffer control A/S, and the slip rate 5 = (109) at the time of requesting the slip control by the brake are respectively unchanged in the example. On the other hand, the target slip by the brake The rate SBT and the engine's slip rate SET, as well as the slip rate SS at the start of slip control, change depending on the road surface conditions, etc. In Fig. 7, as an example, r
O, 17'', ro, 06J or rO, 2J. Then, the slip rate at the start of slip control is S=0.
2 uses the slip rate at the time when the maximum grip force is generated when using a spiked tire (see the solid line in Figure 15).In this way, the slip rate at the start of slip control is increased to 0.2. This is in order to find the actual slip rate when this maximum grip force is obtained, and according to the slip rate when this maximum grip force is generated, the target slip due to the engine and brake = i S
ET and SET are corrected. The solid line in FIG. 13 shows how the grip force and lateral force (expressed as the coefficient of friction against the road surface) of spiked tires change in relation to the slip rate. Also, the first
The broken line in Figure 5 shows the relationship between grip force and lateral force when using normal tires.

(Hereinafter, blank spaces) Based on the above, FIG. 7 will be explained as time goes on.

(i) t □ −t 1 Since the slip rate S does not exceed S=0.2, which is the condition for starting slip control, slip control is not performed. That is, when the slip of the drive wheels is small, acceleration performance can be improved by not controlling the slip (driving using a large grip force). Of course, at this time,
The characteristics of the throttle opening relative to the accelerator opening are as follows:
It is uniformly determined as shown in the figure.

(2) t 1 - t2 Slip control is started and the slip rate is during slip control by the brake [point E (S=0.09) or higher]. At this time, since the slippage is relatively large, slip control u1 is performed by the low torque generated by the engine and braking by the brake.
Since the target slip of the brake -<< (S=0, 17) is larger than the target slip of the engine = 4<(S=0.06), the brake is applied when there is a large slip (S>0, 17). When pressed or with a small slip (S<0
, 17), the brake is not pressurized and the slip is controlled only by the engine so that the slip converges.・(3
) t 2 to 14 (Recovery control gg) In this embodiment, the convergence of the slip is detected by the slip -jZ S, and a predetermined period of time ( For example, during a period of 170 m5eC), recovery control is performed in which the throttle valve 13 is maintained at a predetermined opening degree by oven loop control. Then, S=O/2 (maximum acceleration G M at time t2)
AX is determined, the maximum grip of the road surface (maximum grip force of the drive wheels) is estimated from this G MAX, and the throttle valve 13 is opened IfS'' (optimum throttle opening) to generate the maximum grip force of the drive wheels. TV, ) are set.

This kind of recovery control prevents a drop (overshoot) in the vehicle acceleration G immediately after the slip settles, and also improves acceleration by ensuring a predetermined torque before the slip settles. .

1-The optimal throttle opening TVo for realizing the output torque to the drive wheels that can generate the maximum grip is theoretically determined from the torque curve of the engine 6 and the gear ratio. The decision should be made based on the map shown in Figure 17. This map was created using an experimental method, and G WAX is 0.
When it is 15 or more F and 0.4 or more, the total of G MAX is 111
11 errors are taken into account, the value is set to a predetermined constant value. The map shown in FIG. 17 is based on the assumption that the vehicle is at a certain gear position (for example, 1st gear), and the optimum throttle opening degree Tvo is corrected at other gear positions.

(4) t4 to t7 (backup control, buffer control) The control shown here is performed in order to cope with the case where the slip: 4AS becomes abnormally low t, and usually shifts from the recovery control described above to feedback control.

In other words, backup system '4a (open loop system g
o) When Sho becomes 01, the feedback control is stopped and the throttle valve 13 is opened in stages. When the slip rate is between 0.01 and 0.02, buffer control is performed to smoothly transition to the next feedback control (14 to t5 and I
ts~t7). This backup control is performed when neither feedback control nor recovery control can deal with the problem. Of course, the response speed of this backup control is seven times faster than that of feedback control.

In this embodiment, the rate of increase in the throttle opening in this backup control is set to 0% with respect to the previous throttle opening at every 14 m5 ec of sampling time of the throttle opening.
．． It is assumed that an additional amount of 5% opening is added.

In addition, in the above-mentioned buffer control, as shown in FIG. 18, the throttle opening degree T2 obtained by the feedback control calculation and the throttle opening degree T1 obtained by the backup control calculation are proportionally determined by the current slip = i & So. The throttle opening degree To is obtained by distributing the throttle opening.

(')) t7-t8 Even when the slip rate is abnormally reduced, by performing the control up to t7, there is a smooth transition to slip control (feedback control) using only the engine.

Since the accelerator 69 was fully closed by the driver after +81 t B, the slip control was turned off. At this time, throttle valve 1
Even if the opening degree of No. 3 is left to the will of the driver, there is no danger of t) slipping because the torque has been sufficiently reduced. In addition,
In the slip control, in the embodiment, in addition to fully closing the accelerator, the target throttle opening due to the slip control is
The 12th one corresponds to the accelerator opening degree operated by the driver.
This is done even when the throttle opening is smaller than the throttle opening determined by the figure.

Details of slip control (flow chart) Next, Figure 8~
The details of the slip control will be explained with reference to the flowchart in FIG. 13. In the embodiment, when the car 1 is stuck in mud or the like, brake control is used to escape from the mud or the like. It also controls the stack for this purpose. Note that in the following explanation, P indicates a step.

FIG. 8 (Main) After the system is initialized at the PI, it is determined at P2 whether or not the system is currently stuck (a state where it is stuck in mud or the like and cannot move). This determination is made by checking whether a stack flag, which will be described later, is set. When the determination in P2 is NO, it is determined in P3 whether or not the accelerator 69 is fully closed. When the determination in P3 is No, it is determined in P4 whether or not the current throttle opening is greater than the accelerator opening. If the determination in P4 is No, it is determined in P5 whether or not slip control is currently being performed. This determination is made by checking whether the slip control flag is set. When the determination in P5 is No, it is determined in P6 whether or not a slip has occurred that requires slip control. This determination is made by checking whether slip flags for the left and right front wheels 2.3, which will be described later, are set. This P6
If the determination is No in step P8, the program moves to PI and resets the engine control flag (Ec), and then the slip control is stopped in step P8 (normal driving).

When the determination is YES in P6, the process moves to P9 and the slip control flag is set.

Subsequently, in Plo, the initial value of the target slip jlsET for the engine (throttle) (0.06 in the example)
) is set, and the initial value (0.17 in the example) of the target slip rate SET for the brake is set at pH. After this, brake control is performed at PI2 and engine control vll is performed at PI3 for slip control, as will be described later. Note that the initial values for PIO and pH are set based on the maximum acceleration G MAX obtained in the previous slip control from the same viewpoint as P77 described later.

At P5, the slip control flag indicates YES.
When it is determined that this is the case, the process moves to the above-mentioned PI2, and the slip control is continued.

If YES is determined in P4, the slip control is no longer needed, and the process moves to PI5. This PI
5, the slip control flag is reset. Then,
Engine control is performed at PI6, brake control is performed at PI7, and the engine control flag (Ec) is reset at %P18. It should be noted that this brake control at PI7 is performed as a countermeasure against a stuck situation.

If YES is determined at P3, the brake is released at PI4, and then the processes from P15 onwards are performed.

1i? If YES is determined in P2 of 1., the processing from P16 onward is performed.

FIG. 9 The flowchart of FIG. 9 has 1;η added to, for example, 14m5ec'hj with respect to the main flowchart of FIG.

First, in P21, the capacity values from each sensor 61 to 68 are input for data processing. Next, at P22, slip detection processing, which will be described later, is performed, and then, at P23, throttle control is performed.

FIG. 10 (Slip Detection Process) The flowchart in FIG. 1O corresponds to P22 in FIG. 9. This flowchart is for detecting whether a slip that is subject to slip control has occurred, whether a large slip is converging (27), and whether or not the vehicle is stuck.

First, in P31, it is determined whether the clutch 7 is completely connected. If YES is determined in P31, it is assumed that the stack is not in progress, and the stack flag is reset in P32. Then P3
3, the current vehicle speed is low, for example 6.3 km.
It is determined whether or not the value is smaller than /h.

When the determination in P33 is No, a correction value α for slip determination is calculated in P34 according to the steering angle of the steering wheel (see FIG. 14). After this, in P35, the slippage rate of the left front wheel 2 as the left driving wheel is set to a predetermined reference value of 0.
It is determined whether or not the value is larger than the value (0, 2+α) obtained by adding α in P34 to 2 to P34. With this P35 determination, Y
In the case of ES, it is assumed that the left front wheel 2 is in a slip state, and the slip flag is set. On the other hand, No on P35
When it is determined that the slip state of the left front wheel 2 is converging, the slip flag is reset. Note that the E correction (+fiα) is set in consideration of the rotational difference between the inner and outer wheels (especially the rotational difference between the driving wheel and the driven wheel) during turning.

After P36 or P37, P38, P39, P2O
In P35, the slip flags for the right wheels 15 and 3 as the right driving wheels are set or reset.
This is performed in the same manner as P36 and P37.

If YES is determined in Appendix P33, the vehicle speed is low, and there will be a large error in calculating the slip rate using the vehicle speed, that is, based on equation (1) above. It is intended to be detected only by That is, at P41, the rotation speed of the left front wheel 2 is
It is determined whether the rotational speed is greater than the rotational speed equivalent to a vehicle speed of 10 km/h. When it is determined as YES in this P41, P
At 42, the slip flag for the left front wheel 2 is set. Conversely, when the determination is NO at P41, the slip flag for the left front wheel 2 is reset at P43.

After P42 and P43, the slip flag for the right front wheel 3 is set or reset in P44, P45, and P46 in the same manner as in P41 to P43 described above.

When the determination in P31 is No, there is a possibility that the vehicle is stuck (while the vehicle is stuck, the driver trying to escape from the mud etc. uses a half clutch).

In this case, the process moves to P51, and it is determined whether the rotational speed of the left and right front wheels 2 and 3 as driving wheels is equal (or smaller) (for example, if the speed is 2 km/h or less in terms of vehicle speed). (It is determined whether or not there is one.) When it is determined NO in P51, it is determined in P52 whether or not the stack FuJ is currently being controlled. If P52 is determined as No, P
At 53, it is determined whether the number of revolutions of the front right wheel 1 and 3 is greater than the number of revolutions of the left front wheel 2. When it is determined YES in P53, it is determined whether the rotation speed of the right front wheel 3 is greater than 1.5 times the rotation speed of the left front wheel 2.

If YES is determined in P54, a stack flag is set in P56. On the other hand, if the determination in P54 is NO, it is assumed that the stack is not in progress, and the above-mentioned P3
2 and subsequent processes are performed.

Further, when the determination is No in P53, the number of revolutions of the left front wheel 2 is 1 of the number of revolutions of the right front wheel 3 in P55.
．． It is determined whether or not it is greater than five times. If YES in P55, the process moves to P56, and if NO, the process moves to P32.

After P56, at P57, the vehicle speed is 6.3km/h.
It is determined whether or not it is larger than . YES on this P57
When this happens, the target rotation speed of the front wheels 2.3 is set to be 1.25 times the rotation of the driven wheels, which indicates the vehicle speed.
If the answer is No in P57, then in P59 the front wheel rotation speed is 2.3/11.
It is set at 11' at 10km/h.

Fig. 11 (Brake control) The flowchart shown in Fig. 11 is based on the PI3 of Fig. 8.
and PI7.

First, in P81, it is determined whether t<+ is presently being stacked. If No in P81, in P82, the brake response speed Bn (corresponding to the duty ratio for opening/closing control of SVI to SV4) is set to the mint value (maximum value) as a function according to the vehicle speed (the higher the vehicle speed, the larger it becomes). Set as . On the other hand, if YES in P81, in P83, set the above-mentioned rimint (tflB LM) as a constant value smaller than that in P82.
The process in 2.83 was performed in consideration of the fact that if the Bn calculated by the equation (7) above is used, the brake fluid pressure increase/decrease rate is too fast, which may cause vibrations, etc. Ru. In addition, in P83, it is particularly undesirable for the braking force applied to the drive wheels to change suddenly in order to escape from the stuck state, so a small constant value is set as the limit value.

After P82 or P83, it is determined in P84 whether the slip rate S is larger than 0, 09, which is the brake control stop point. When YES in P84, the operation speed Bn of the right front wheel brake 22 is calculated in P85 (Bn in the I-FD control in Fig. 6).
Japanese name). After this, in P86, the above Bn is "O"
It is determined whether or not the value is larger than that. This determination determines whether or not the brake pressure is increasing, assuming that the brake pressure increasing direction is positive and the pressure decreasing direction is negative.

When P86-rYEs, Bn>B at P87
It is determined whether it is LM or not. When YES in P87, after setting Bn to the limit value BLM, the pressure of the right brake 22 is increased in P89. Also, P87
When the answer is No, the pressure is increased in P89 using the Bn value determined as 1 in P85.

1m, p86, N0c7), Bn is "negative" or "O", so after converting Bn to an absolute value with P2O,
The processing of P91 to P93 is performed. These P91 to F93 are when depressurizing the right brake 22, and P87 and P88
, P89 processing is supported.

After P89 and P93, the process moves to P94, and pressure increase or decrease processing is performed for the left brake 21 in the same way as for the right brake 22 (process corresponding to P84 to P93).

On the other hand, when the answer is NO in P84, it is time to perform the brake control in the middle, so the brake is released in P95.

In addition, between P85 and P86, the actual rotation speed and target rotation speed (actual slip rate and target slip rate) of the driving wheels
When the difference is large, it is preferable to make a correction such as reducing the integral constant KI in equation (5), for example, in order to prevent deterioration in acceleration and engine stalling due to excessive braking.

Fig. 12 (Engine control) The flowchart shown in Fig. 12 is based on the PI3 of Fig. 8.
It corresponds to

First, in P61, the engine control flag (Ec) is set, and then in P62, as mentioned above,
By resetting the slip flag, it is determined whether or not the slip has transitioned to a converged state (whether or not it has passed time t2 in FIG. 7). If this P62 is No, P63
In , it is determined whether the slip rate S of the left front 1 theory 2 is greater than 0.2. If P63 is No, P64
Then, it is determined whether or not the slip rate S of the right front wheel 3 is greater than 0.2. If NO in P64, it is determined in P65 whether only one of the left and right heavy wheels 2.3 is under brake control, that is, whether the vehicle is traveling on a split road. When YES in P65, the current slip rate is calculated in P66 using the drive wheel with the lower slip rate among the left and right front wheels 2.3 as a reference (select low). Conversely, if P65 is No, the left and right front wheels 2.
3, the current slip-Ji is calculated according to the drive wheel with the larger slip ratio (SELECT Q\"a). Note that even if P63 and P64 are No, the process moves to P67.

1- Select high at P67 calculates the current slip rate to suppress the slip of the slippery drive 1, thereby making it possible to further avoid using the brake. On the other hand, the select low setting in P66 above is effective when driving on a split road where the friction coefficients of the road surface that the left and right drive wheels contact are different, while suppressing the slip of the drive wheel that is more likely to slip using the brake. This makes it possible to drive by taking advantage of the grip of the drive wheel on the weaker side. In addition, in the case of this select low, in order to avoid overusing the brakes, it is advisable to take backup measures such as limiting the select low to a certain period of time, or stopping the select low when the brakes overheat.

After P66 and P67, it is determined in P68 whether the current slip ratio S is greater than 0.02. When YES in P68, the throttle valve 13 is feedback-controlled for slip control in P69. Of course, at this time, the throttle valve opening degree (T n ) is the same as the target slip j set in P66, P67't' or changed in P77, which will be described later.
It is set to realize KsET.

If No in P68, it is determined in P2O whether or not the current value j<S is greater than 0.01. If YES in P2O, the buffer control described above is performed in P71. Also, if P2O is No,
At P72, the backup control described above is performed.

On the other hand, if YES in P62, it is assumed that the large slip of the drive wheels is converging, and the process proceeds to P73, where the recovery control is performed. That is, first P7
In step 3, it is determined whether or not a predetermined time (the time for performing the refill/reduction control, which is 170 msec as described above in the embodiment) has elapsed after the shift to the slip convergence direction. P73
When the answer is No, the processing from P74 onward is performed to perform recovery control. That is, first, at P74, the maximum acceleration G MAX of the automobile 1 is measured (at time t2 in FIG. 7). Next, in P74, the optimum throttle opening degree Tvo is set so that this G MAX can be obtained (see FIG. 17). Further, at P76, the optimum throttle opening T at P75 is determined according to the current gear position of the transmission 8.
v□ is corrected. In other words, due to the difference in gears,
Since the applied torque to the drive 1 gear is also different, P75 is the optimum throttle opening Tv for the gear position of the monk.
is set, and this difference in gear position is corrected in P76. After this, in P77, G in P74
The friction coefficient of the road surface is estimated from MAX, and the subsequent target slip control rate SET and SET for engine (throttle) and brake control are both changed.

The target delivery rate of the engine and brake that is changed in this P77 is SET. SET is changed, for example, as shown in FIG. 19 based on the maximum acceleration G MAX measured at P74. As is clear from Fig. 19, as a general rule, the larger the maximum acceleration GMAX, the higher the torque.
Veri rate S ET. The idea is to increase SBT. And the veri rate SET.11. Each SST is designed to have its own limits.

If YES in P73, the recovery control line is set to r, and the processes from P63 described above are performed.

Slot 1 control (Figure 1-3) The flowchart shown in Figure 13 is based on P23 in Figure 9.
It corresponds to

First, in P24, it is determined based on the engine control flag (Ec) whether slip control or normal running control is currently in progress. When this P24 is YES (slip control), control of the throttle/leave 13 is selected in order to realize the predetermined 11 target verity rate SET, and the control method is the I-FD control method (first control means). selected, and according to the above equation (2), (according to which throttle operation: 5 M
The previous page of n is made.

On the other hand, when the result in P24 is No (normal driving control),
In order to leave the opening/closing control of the throttle valve 13 to the will of the driver, control that achieves the target throttle opening according to the characteristics shown in FIG. 14 is selected, and the control method is based on the PI.
Control method D (second control means) is selected, and the throttle operation amount Mn is calculated based on equation (3).

As a result, the I-FD has excellent stability in slip control.
The opening and closing of the throttle valve 13 is controlled by the control method, and in normal driving control, the opening and closing of the throttle valve 13 is controlled by the PID control method, which has excellent response speed. Therefore, during normal driving, responsive engine characteristics can be obtained, while in slip control, it is possible to improve slip control and prevent re-slip.

Although the embodiments have been described above, the present invention is not limited thereto, and includes, for example, the following cases.

(1) When adjusting the torque generated by the engine as an adjustment of the output torque to the drive wheels of the power plant system, it is preferable to change and control the star map that has the most influence on the output generated by the engine. In other words, it is preferable to adjust the generated torque by so-called load control, by adjusting the mixture amount in the case of an engine with an automatic engine (for example, a gasoline engine), and by adjusting the fuel injection amount in the case of a diesel engine. is preferred. However, this load control is not limited to this, and may be carried out by adjusting the ignition timing in the case of an engine with a complete engine, or by adjusting the fuel injection timing in the case of a diesel engine. Furthermore, in engines that require supercharging, this may be done by adjusting the supercharging pressure. Of course, the power source is not limited to an internal combustion engine, but may also be an electric motor, and in this case, the generated torque may be adjusted by adjusting the power supplied to the motor. Further, the adjustment may be performed not only by adjusting the engine but also by adjusting the connection state of the clutch 7 and the gear ratio of the transmission 8. In this case, a continuously variable transmission (CVT) is particularly preferred.

(?) In a car, the front wheels 2.3 are not limited to driving wheels, but the rear wheels 4.5 may be driving wheels, or even if all four wheels are driving wheels. good.

(3) To detect the slipping state of the driving wheels, it is possible to directly detect the rotational speed of the driving wheels as in the embodiment, but there are other ways to detect the slipping state depending on the state of the vehicle. Preliminary 1!
11, that is, it may be detected indirectly. Such vehicle conditions include, for example, an increase in the generated torque or rotational speed of the power source, a change in the accelerator opening, a change in the rotation of the drive shaft, and the steering condition (cornering).
Possible factors include the floating state (acceleration) of the vehicle body, product/acid content, etc. In addition, it is also possible to automatically detect or manually input road surface conditions such as high and low atmospheric temperatures, rain, snow, etc. to make the prediction of the slip state of the drive wheels even more appropriate. can.

(Effects of the Invention) As is clear from what has been described below, the present invention makes it possible to select a control method according to the respective requirements of slip control and normal running control. It is possible to aim for

1) Simple explanation of 4 drawings FIG. 1 is an overall system diagram showing one embodiment of the present invention.

7jr, FIG. 2 is a diagram showing an example of a brake fluid pressure control circuit.

Figure 3 shows the first control method (
FIG. 3 is a block diagram showing I-FD control.

Figure 4 shows the second control method (
FIG. 3 is a block diagram showing PID control.

FIG. 5 is a block diagram when performing feedback control of the throttle valve.

FIG. 6 is a block diagram when feedback controlling the brakes.

FIG. 7 is a graph schematically showing a control example of the present invention.

8 to 13 are flowcharts showing control examples of the present invention.

FIG. 14 is a graph showing the characteristics of throttle opening relative to accelerator opening when slip control is not performed.

FIG. 15 is a graph showing the relationship between the grip force of the driving wheels and the lateral force in terms of the relationship between the slip rate and the coefficient of friction with respect to the road surface.

FIG. 16 is a graph showing correction values when the slip rate at the start of slip control is corrected according to the steering angle of the steering wheel.

FIG. 17 is a graph showing the optimum throttle opening corresponding to the maximum acceleration during beam/edge control.

FIG. 18 is a graph showing the relationship between slip rate and throttle opening when performing buffer control.

FIG. 19 is a graph showing an example of a map used when determining the target slip rate.

FIG. 20 is an overall configuration diagram of the present invention.

car to 2.3: Front wheel (drive wheel) 4.5: Rear wheel (driven wheel) 6: Engine 7: Clutch 8: Transmission 13: Throttle valve 14 Nisthrottle actuator B1: Sensor (throttle opening) 62: Sensor (clutch) 63: Sensor (gear stage) 64.65: Sensor (drive wheel rotation speed) 66: Sensor (driven wheel rotation speed) 67: Sensor (accelerator opening) 68: Sensor (handle steering angle) 69: Axel U: Control unit Figure 2 Figure 9 Figure 13 Figure 14 Hand I Shizo E Xi Figure 15 S (choberi 4'-) Figure 17 MAX Figure 18 To τ quickly (S) Figure 19 MAX

Claims (1)

[Claims] (1) A slip control device for an automobile that prevents excessive slip of the driving wheels on the road surface by controlling the output torque to the driving wheels of a power plant system including at least an engine, wherein the power plant system includes: a torque adjusting means for adjusting the output torque of the power plant system; and a means for controlling the output torque of the power plant system.
It has a first control means that emphasizes stability and a second control means that emphasizes response speed, and the first and second control means are switchable between slip control and normal running control. An automobile slip control device characterized by: